The several families of Thomsons of the Isle of Arran were all descended from a certain Lachlan MacTavish, who had come out of Argyll ca 1667. The following excerpts explain that the MacTavish of Arran took the name of Thomson, or were alternately known as Thomsons, and that they had moved on. There were no MacTavish alias Thomson families living on Arran in 1936.

We have already seen one way of their coming as settlers ; another report is that MacAlisters came over to Shisken from their home country in the south side of Loch Tarbert to fill up places vacant by a destructive visit of the plague in 1666. The year preceding is that of the Great Plague of London, but there is no record of the infection having passed to Scotland. But the MacAlisters had been so often a plague to the island that it was fitting such a forerunner should prepare a place for them. Other families credited with occupying these sorrowful vacations are Thomsons and MacMillans, while Bannatynes came from Rothesay. But no doubt there was normally, from time to time, an infusion of Kintyre and Cowal blood in Arran. The ecclesiastical connection between Saddell and Shisken would be one channel. Several families of the name of Thomson are descended from Lachlan MacTavish or Thomson, a shepherd brought over from Skipness by Hector MacAlister (Eachann Og), tenant of Moine-choille and Glaster. Lachlan, after some time, married a relative of his employer's wife, and later on, being desirous of acquiring a farm, got the sympathies of his own and his master's wife enlisted to the end that Eachann Og should solicit this favour for him. During a visit to the castle Eachann Og did so, with the result that some families of MacGregors and MacAlisters were removed from their holdings in Achancar (sic Achincar) to make room for Lachlan MacTavish or Thomson. (Achincar for clarity, see following: CLANS OF SHISKINE) (pp 114,115.)

In 1849 there was still living, at Kildonan, Lachlan Thomson, a veteran of the crew of the frigate Shannon, who had been present at her capture of the American Chesapeake on June 1, 1813.1 (p. 127)

(Note of interest: The American 38-gun Frigate USS Chesapeake, was captured by HMS Frigate, Shannon, in a single ship action on 1st June 1813. This two ship action remains one of the bloodiest of the war of 1812, and the numbers of casualties aboard both ships remained the worst for any single ship action for years. Among the USS Chesapeake dead, was her captain, James Lawrence, whose dying words were "Don't give up the ship!" It has been a rallying cry in the US Navy ever since.)

CLANS OF SHISKINE
PAST AND PRESENT
-Extracted from Parts 1 and 2-

Compiled and read by
Mr. Charles Robertson, Burncliff, Shiskine, Isle of Arran,
to the Natives of Arran in Glasgow, March, 1936

From Part 1, p. 1.- Mr Chairman and friends:- It gives me the greatest pleasure to be here this evening. I invariably read the reports of your meetings, and they seldom fail to strike a sympathetic note, as each and all of us are intensely interested in all that concerns our native Island. I am especially pleased to have in the chair this evening my friend and kinsman, Duncan Thomson. In fixing the title of my address, I had at the back of my mind the feeling than nothing could interest my audience more than to hear something (to use a Scripture phrase) of the rock from whence most of us were hewn. The subject must have a local setting. I therefore, at the outset, crave the indulgence of those from other parts of the Island. Yet I hope my whole survey will make a general appeal.

From Part 2, p. 3 - THOMSON. The Thomsons came to Arran from Argyllshire, farmed in Auchincar. There are no Thomsons in the district now. One cannot mention clans without associating certain christian names with those clans, for instance, you could not think of Bannatynes without Ebenezers and Ronalds; M'Alisters without Hectors and Matthews; M'Kenzies without Gilberts and Angus; Robertsons, Archibalds and Charles; Sillars without Malcolms; and Curries without Johns and Donalds, and M'Brides without Peters. I was very surprised at finding so many Old Testament names among the Christian names of the clans of Arran.

Note: It appears that Duncan Thomson, mentioned in Part 1, as friend and kinsman to Mr. Charles Robertson, Burncliff, Shiskine, Arran, is a direct descendant of the several families of Thomsons sprung from Lachlan MacTavish (also called Thomson), who had initially settled at the farm of Achancar (Achincar) about 1667, recalled in the Book of Arran. Duncan Thomson now appears living in Glasgow.